Abstract: A multi-beam optical system is provided with reflecting mirrors and separating mirrors on optical paths of light beams for each color so that the difference of the numbers of reflections of the scanned light beams for the respective colors when they penetrate through the lens and reach the photosensitive drum can be the same or an even number. The ference of the number of reflections of the scanned light beams for the respective color can become an even number and the scanning lines are distorted in the same direction by the lens, and are thus not liable to lose a parallel relation between the line images.

Abstract: A copying apparatus having an interrupt copying function is disclosed which comprises a memory for storing copying conditions, an input device for inputting copying conditions, a copying control for performing copying operations according to stored copying conditions, a memory for storing interrupt copying conditions, a mode selection devices for selecting the interrupt mode, and a system for making, when the interrupt copying mode is selected, initial setting of copying conditions for the interrupt copying operation by setting up copying conditions that are stored in the memory for interrupt copying conditions in the aforementioned memory for copying conditions, whereby the operation for storing copying conditions is simplifed or can be eliminated.

Abstract: A laser beam scanning apparatus for laser printers, digital copying machines and the like in which a plurality of laser beams are combined, the composite laser beam is deflected in the main scan direction and a part of the deflected composite laser beam enters an optical path at an SOS signal sensor, then the composite laser beam is split and directed to different parts of an exposure member. Although there is some mixing of one beam split from the composite beam with unsatisfactorily separated beam, the unsatisfactorily separated beam is further separated in the optical path to the exposure member, thus effectively preventing the occurrence of image ghosts on the exposure member.

Abstract: An image duplicating apparatus including a device for designating a localized area of a document sheet bearing visible images, a first input for entering conditions relating to the formation of the images within the designated area, a second input for entering conditions relating to the formation of the images outside the designated area, and image reproducing sections capable of duplicating the images on the whole area of the document sheet onto a single face of a copying sheet, wherein the images within the designated area of the document are duplicated onto the single face of the copying sheet in accordance with the conditions entered by the first input and the images outside the designated area of the document are duplicated onto the single face of the copying sheet in accordance with the conditions entered by the second input.

Abstract: A copying machine has a simultaneous color mode for forming multi-color images in a single copy cycle and especially selects and releases the simultaneous color mode. An index, which is movable in the scanning direction of a document, is operated to automatically select the simultaneous color mode and set the switching position thereof. In addition, the index is moved out of a document area to automatically release the simultaneous color mode, which enables the simultaneous color mode to be easily selected and released. As a result, the miscopying of a document caused by a mistaken operation in selecting or releasing the simultaneous color mode can be prevented.

Abstract: A document detecting device for an image forming apparatus operates when a sensor supporting arm equipped with sensors is pivoted to a predetermined position below a document, the document size or the density of the image is detected by the combination of the detection results of the sensors. One of the combinations which is not used for the document size or density detection is used to detect that the sensor supporting arm is at its original position. This construction avoids such an error that the sensor supporting arm is misinterpreted as being at its original position when an irregular sized document is set.When a new document is set, the data indicating the previous document size is accurately updated by the combined use of two switches. The first switch detects whether a document holding cover is opened less than a predetermined angle. The second switch detects whether the cover is completely closed.

Abstract: An improved electrostatic photo-copying machine is proposed. In this improved photo-copier, an optical system for scanning a document from which photocopies are to be made is provided. However, the movable range of the optical system is divided into a front half and a rear half, adapted for execution of successive scannings so as to provide a book copy mode operation. If, however, an incompatible operation to the book copy mode, for instance, manual feed of any suitable size copy paper through a manual feed opening; automatic document feed mode or the like has been specified, the once and in advance selected-out book copy mode is automatically released from service.

Abstract: A control system for a machine includes a pulse generator for generating a pulse signal synchronized with the speed of drive of the machine and a programmed control device for receiving the pulse signal and controlling the sequence of operation of the machine thereby to synchronize the control operation of the control device and the actual operation of the machine with each other. For this purpose a program of the programmed control device is so designed that a control routine for executing a process necessary to control the machine and a synchronizing routine for controlling the timing at which said control routine is to be started are executed continuously and repeatedly. The routine of the program are so associated with the pulse generator that the number of pulses generated at a speed corresponding to the normal run of the machine during the time equal to the sum of the control routine and the synchronizing routine is at least two.

Abstract: A heat roller fixing device comprising a changeover arrangement to be selectively changed over in accordance with thickness of a copy paper, and a control circuit for causing a heating roller and a pressure roller in pressure contact with the heating roller to rotate when the changeover arrangement has been changed over to a thick paper and for stopping the rotation of the heating roller and pressure roller when the surface of the heating roller has reached a predetermined temperature.

Abstract: An improved copying machine is provided to eliminate problems associated with an erroneous indication of paper misfeed. Control means is provided for rendering a jam detection circuit inoperative when it is determined the copy paper is absent in the storage tray after the start of the copying cycle and before the introduction of the copy paper into the copying machine.

Abstract: A counter control device for use in an electrophotographic copying machine operable selectively in one of a multi-copy mode wherein a copying operation is repeated to produce a plurality of copies with copying papers being automatically fed one at a time and a manual feed mode wherein the copying operation is carried out by the use of copying papers fed manually one at a time. The counter control device includes a multi-copy mode counter, a manual feed mode counter and a display unit capable of displaying the number of copies to be made not only in the multi-copy mode but in the manual feed mode, thus eliminating the need for utilizing any other complicated counter device or special display unit.